Trouble getting power to the pumps

speedjunkie · 09-30-2014, 11:07 PM

During a rebuild I decided to rewire my fuel pumps again, and followed Cohbra's write-up here...

http://www.rx7club.com/3rd-generatio...lights-998596/

I'm having no problems with that part of the system, my problems start in the stock part of the wiring.

When trying to start the car after the new rebuild, we were having issues starting it with the Adaptronic and thought maybe the injectors weren't firing or something, so I put my old PFC back in and I either got no fuel pressure right away, or it happened shortly after, I don't remember which. Either way, I jumped F/P and GND in the diagnostic box and got fuel pressure and we started the car on that and it actually ran perfectly. I troubleshot the lack of fuel pressure that time for a few days and then remembered the problem seemed to show when I put the PFC in. I swapped the Adaptronic in and I got fuel pressure again, but still haven't been able to start the car. The other night, the no fuel pressure problem came back. After troubleshooting, we've traced it to the green circuit opening relay (or fuel pump relay as it's called in the 93 manual), but I tried three different known-good green relays and none of them cured the problem.

I made this to show where I get voltage, but it doesn't show everywhere because I mainly checked the green and yellow relays.

This one shows where I understand the power to go (in red, and correct me if I'm wrong), and if I jump the green relay, where the power goes from there (in blue).

While doing the rebuild, I noticed a couple wires that got damaged by the driver's side wheel, so I'm thinking this might have something to do with my issues.

I also had some issues with slow cranking, but I got a new ignition switch and it seems to have fixed that problem. Although sometimes the problem was intermittent before, so only time will tell if it's truly fixed.

I did continuity checks on the wiring and it all seems to be good. For some reason the green relay just isn't closing and it happened out of the blue and with both ECUs. I might put in a stock ECU just to see if it'll start.

I'm really stumped as to why this is happening. Does anyone that's better with wiring have any ideas?

09-30-2014, 11:07 PM	#1
speedjunkie RCC Loves Me Not You Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (1) Posts: 2,089 Rep Power: 19	Trouble getting power to the pumps During a rebuild I decided to rewire my fuel pumps again, and followed Cohbra's write-up here... http://www.rx7club.com/3rd-generatio...lights-998596/ I'm having no problems with that part of the system, my problems start in the stock part of the wiring. When trying to start the car after the new rebuild, we were having issues starting it with the Adaptronic and thought maybe the injectors weren't firing or something, so I put my old PFC back in and I either got no fuel pressure right away, or it happened shortly after, I don't remember which. Either way, I jumped F/P and GND in the diagnostic box and got fuel pressure and we started the car on that and it actually ran perfectly. I troubleshot the lack of fuel pressure that time for a few days and then remembered the problem seemed to show when I put the PFC in. I swapped the Adaptronic in and I got fuel pressure again, but still haven't been able to start the car. The other night, the no fuel pressure problem came back. After troubleshooting, we've traced it to the green circuit opening relay (or fuel pump relay as it's called in the 93 manual), but I tried three different known-good green relays and none of them cured the problem. I made this to show where I get voltage, but it doesn't show everywhere because I mainly checked the green and yellow relays. This one shows where I understand the power to go (in red, and correct me if I'm wrong), and if I jump the green relay, where the power goes from there (in blue). While doing the rebuild, I noticed a couple wires that got damaged by the driver's side wheel, so I'm thinking this might have something to do with my issues. I also had some issues with slow cranking, but I got a new ignition switch and it seems to have fixed that problem. Although sometimes the problem was intermittent before, so only time will tell if it's truly fixed. I did continuity checks on the wiring and it all seems to be good. For some reason the green relay just isn't closing and it happened out of the blue and with both ECUs. I might put in a stock ECU just to see if it'll start. I'm really stumped as to why this is happening. Does anyone that's better with wiring have any ideas?